The present invention relates to a semiconductor device and a manufacturing method thereof, and particularly to a semiconductor device (double-sided electrode package) having a double-sided electrode structure and a manufacturing method thereof.
With miniaturization of electronic equipment such as a cellular phone, the development of three-dimensional package techniques with a higher packaging density has recently been underway. Of the three-dimensional package techniques, a method called “package on package (POP)” in which another package is stacked on one package is promising. In the POP, there has also been proposed laminating of packages extending to a multilayer like three layers or four layers (refer to a patent document 1 (Japanese Unexamined Patent Publication No. He 11(1999)-260999)).
A typical structure of a conventional POP is shown in FIG. 18. Another package 2 is stacked on a package 1 in this POP structure. A semiconductor chip is flip-chip connected in the package 1 located on the lower side. The package 1 is provided with solder balls as connecting terminals on its back side and provided with land portions with solder paste applied thereto on its surface side.
In the package 2 located on the upper side, a semiconductor chip is wire bond-connected and sealed with a resin. Even in the package 2, land portions are provided on its back side as connecting terminals. The land portions of the package 2 are provided at positions opposite to those of the package 1 in a stacked state. The land portions of the package 2 are respectively electrically connected to the land portions of the package 1 by means of solder balls 3.
The conventional POP however involves various problems. They are as follows: for example, (1) since packages are stacked on each other, a mounting height cannot be lowered as compared with the stacking of semiconductor chips, (2) when warpage occurs in each package, the reliability of electrical connections is degraded, (3) since the lower package becomes insufficient in sealing, moisture-resistant reliability is degraded, and (4) since there is a limit to reduce the diameter of each of the solder balls provided in each package as the connecting terminals, the conventional POP is not adaptable to a multi-pin configuration of the semiconductor chip. Any of these problems is attributable to the structures of the laminated packages.
A double-sided electrode package is used in the POP. The double-sided electrode package includes at least inner wirings connected to each semiconductor chip, through electrodes which connect electrodes and inner wirings on the package surface side, and through electrodes which connect electrodes and inner wirings on the package back surface side. In order to solve the problems of the prior art POP, there is a need to develop a double-sided electrode package having a structure excellent in reliability, productivity and general versatility.